Island



.PATENTED APR. 2, 1861.

T- WILLIAMS. ING DEAD CENTERS IN GRANKS.

MEANS FOR AVOID To all whom it may co'ncer UNITED. STATES PAT NT OFFI E';

IMPROVEMENt-ilN-MEANS FORAVOIDING THE DEAD-CENTERS INCRANKS.

Specification forming part of Letters Patent No. 3!,926, dated. April 2, lent. I

Be it knownthat I, TURNER WInLIaMsfof Providence, in the county of Providence and State of Rhode Island, have invented a new Y -parts thus far described do not differ in any and useful Improvement in Means for Avoiding the Dead-Centersin Cranks, which is ap-v plicable to sewing-machines and others of a. similar character when a crank operated by a t-readle is employed fordriving the same; and 1 do hereby declare that the followingis afull, clear, and exact description of the said improvement, reference being had to the annexed drawings, forming part of this specification, in which- Figure] is aside elevation and section of the frame and workin g parts of a sewing-machine with my improvement. Fig. 2 is a like view of. the working parts detached from the frame and occupying a dilierent relative posi- 'tioirfrom that of Fig.1. Figs. 3, 4, 5, 6 represent my improvemeutin detail.

Similar letters of reference denote like parts in all the figures.

My invention consists in arranging a spring with a stiff rod extendiri g at'right angles from its loose end in such relative position with respect to a crank to which it is directly connected that the said device shall'operate alternatelyin opposite directions with the revolotion of the crankto carryit past both deadeenters. without stopping, the said force, combinedwith the action of the treadle, producing very nearly the action of the human hand in turning a crank and, an equally regular motion therewith.

To enable'those skilled in the art to make and'use my invention, I will proceed todescribe its construction and operation.

A A! represent the'tablea'nd frame of a sewing-machine as usually constructed, (the opposite side piece corresponding with Abeing omitted to givean unobstructed view of the working parts.) The two side pieces are fastened together by means of screws passing i through lugs upon the frame at a a into the table'at the top,- and by the rod a at the bottom, extending from one side piece to theothcr and fixed at the ends in each.

','B is the crank-shaft, revolving in suitable bearingsformed in the side pieces, A. G is thebalanee-wheel, and D the driving-wheel, upon said shaft.

b the crank, connected by the rod e tothe .treadle L, which vibrates upon the retina, as

shown. p

-The construction and arrangement of the essential particular from those in general use for the purpose. a v

fis a straight flat'spring, as shown in Fig.

4, which is attached at one end to the standd in a swin gin g joint beneaththe table, as shown in Figs. 1 and 2'. A rod, g, isattached to the loose end of this spring f by means of a-washer upon each side of the spring and aunt. to set them together,-and extends at rightangles, or nearly so, therefrom, connecting in-a swinging joint with the rod 0, near the crank-pin, means of the casting t. i

The parts above just described arranged in v the relative position to the crank shown in Figs. 1' and 2 constitute myimprovemeut, and

in the form so presented can be attached to all forms of cranks now employed for this or similarpurposes. j 4

The operatio'not' the'machine may be thus described: Fig. 1 represents the crank-pin as having passedth e quarter-center and approaching the upper dead-center, 2, m do1ng which the sprin g. f is strained and made to as.-

su me the formand position shown. The spring foot upon the treadle which next follows, and

thecrauk is carried from the position ath, Fig. 1, past the quanter-center to the position shown .in Fig. 2, which movement curves-and strains the spring in the opposite direction to that shown in Fig. 1, the force of which moves the crank in the direction indicated by the arrow past the dead-center 3 to the position shown in dotted lines, whenthe treadleresutnes its action, and the crank is moved past the quarter-center to the position shown in F g.1,

from whenceit started, thus completing a IBVOf lution.

It will'be observed that the spring, in the act of carrying the crank past the dead-centers,

- is returning to its natural condition shown in the dotted lines in each Figs.-1 and 2, after being strained in passing the previous quarter'- center, and that the same strain is put upon the springin passing each quarter-center, bending the spr ingin opposite directions alternately. It will also be noticed that the spring. furnishes the force simply, and the rod 9 directs said force withrespect to the object to be moved and the direction in which it is to move. If the sprin g exerts a greater degree of force upon one dead-center than in passing the may take theplaceof the spring and the spring that of the rod, and the resultis the same; or the spring and rod may be of one piece or spring bent at right angles at the point where ;distributed.by the rodg with respect to the two dead-centers,

Having thus described the construction and operation of my improreddevice, what I claim as my invention, and desire to secure by Letters Patent, is-- The use of a spring combinedwi'tha'roll'for directing its force, orthe equivalent thereof, arranged relatively with the ,crank' substantially as herein described. to efl'ectthe purposeset forth. H

TURNER WILLIAMS.

Witnesses: Y

DAVID-HEATON, 2d, ISAAC A. 'BROWNELL. t 

